1. Field of the Invention
The present invention relates to electronic communication systems. More particularly, the present invention is related to a method and apparatus for stably controlling electric power in a mobile device having a Subscriber Identity Module (SIM).
2. Description of the Related Art
Mobile devices such as mobile communication terminals, Personal Digital Assistants (PDAs), etc. have been widely used because they can be easily carried about and provide a variety of functions. For example, mobile communication terminals are equipped with modules for supporting mobile communication that can perform transmission and reception of voice signals and data between mobile communication terminals via a base station. These devices each include a CPU, a memory, and other components, and are operated by an Operation System installed thereto. In addition, there can be a variety of applications based on the OS. Particularly in the case of PDAs, the capabilities include performing information collection, storage, writing operations, search operations, etc.
Conventional mobile devices support a mobile communication function or a particular user function using applications stored in their storage unit. Conventional mobile devices are operated using a Subscriber Identity Module (SIM) that can provide compatibility between mobile devices when the user replaces his/her mobile device with another. Such conventional SIM-based mobile devices have problems in that they frequently experience fluctuation in electric power provided from their power source during operation. In order to support a mobile communication function, the conventional SIM-based mobile devices must supply power that exceeds a certain level to the RF communication unit in order to search for a base station. However, in certain situations, a case occurs where the conventional SIM-based mobile devices may consume a large amount of power during search operations. In that case, the conventional SIM-based mobile devices cannot supply the usual amount of power to the SIM, and thus cannot perform normal data communication with the SIM.